In the preceding paper, the author proposed the method of determination of the control section in the over-flow from dam crest by applying to potential flow theory and estimation of the discharge coefficient in consideration of boundary layer development, and showed that, in case of that the over-flow depth are small, the decrease of discharge coefficient could be explained well. But, incomplete point still remain, for example, change of control section due to the development of boundary layer, the influence of gravity force on the development of boundary layer and the deviation of stream-line from coaxial circles on the discharge are not considered. In this paper, the author intends to treat the case of broad over-flow spillway with vertical curvature which changed continuously, in considering the velocity component normal to botton surface and the influence of gravity force on the boundary layer development.